It is known to make anhydrides containing additional carboxylic acid moieties and dianhydrides of disubstituted maleic anhydrides by synthesis from simpler compounds. These are disclosed in commonly-assigned U.S. Pat. Nos. 4,596,867 and 4,638,072, which are hereby incorporated by reference. It is also known to make polyimides from dianhydrides and aromatic amines. This is disclosed in U.S. Pat. No. 3,179,634 (1965). British Patent Specification No. 570,858 disclosed various processes for making fiber-forming polymers.
In reviewing these references it is clear that the preparation of anhydrides containing additional carboxylic acid moieties and dianhydrides of disubstituted maleic anhydrides by oxidation of substituted alkenes, i.e., diaryl maleic anhydrides, while retaining their alkene character, has not been contemplated in the prior art. Also, the prior art has not contemplated the preparation of disubstituted maleic anhydride compounds of the structure: ##STR1##
The general object of this invention is to provide novel compounds of maleic anhydride structure and novel derivatives of these compounds which are potentially difunctional in structure and to provide novel amide-imide polymers and polyimides. A more specific object of this invention is to provide amide-imide polymers, vinyl polymers, and polyimides from 2-(3',4'-phthalic anhydride)-3phenyl maleic anhydride, 2,3-di(3-carboxyphenyl anhydride) maleic anhydride, and 1,4-(2,5-dicarboxy) phenylene bisphenyl maleic anhydride.